How to use the proration calculator
- Enter the monthly rent and choose whether you are prorating a move-in (rent from the date through month end) or a move-out (rent from the 1st through the date).
- Pick the move-in or move-out date.
- Choose the day-count method your lease names: actual days in that month, or a 30-day month. Under More options, decide whether the move-in or move-out day itself is charged.
- Read the prorated rent, the daily rate and the table that shows both methods for the same date. Copy, print or save the result.
Formula
Daily rate = monthly rent / days in the count (actual days in the month, or 30)
Move-in days charged = days in the count - move-in day + 1 (charging the move-in day)
Move-out days charged = move-out day (charging the move-out day)
Prorated rent = monthly rent x days charged / days in the count, rounded half up to the cent
With the 30-day method the 31st counts as the 30th. If you choose not to charge the move-in or move-out day, one day is removed from the count. The rounding uses whole cents, so an exact half cent always rounds up.
Worked examples
Move-in on October 15, 2026, $1,500 rent: October has 31 days, so the daily rate is $1,500 / 31 = $48.3871. Days 15 through 31 are 17 days, and 17 x $48.3871 is $822.58. The 30-day method counts 16 days at $50.00 and charges $800.00, a $22.58 difference.
Move-out on October 15: the 1st through the 15th is 15 days, which is $725.81 by actual days or $750.00 with a 30-day month. If the move-out day is not charged, 14 days apply.
February: with a move-in on February 10, 2027 (28 days) the 19 remaining days cost $1,017.86. In February 2028, a leap year with 29 days, 20 days cost $1,034.48.
Edge dates: moving in on the 1st is a full month, $1,500.00. Moving in on October 31 charges one day, $48.39 by actual days.
Actual days versus a 30-day month
The actual-days method divides the rent by the real number of days in the month, so a day costs slightly less in a 31-day month and more in February. The 30-day method treats every month as 30 days, which keeps the daily rate the same all year and is common in accounting and some leases.
The two methods can differ by a few dollars in either direction, as the comparison table shows. Neither is universal. Your lease, your state law or your property manager decides, so read the lease before you rely on one.
Which days count
A move-in date usually counts as a day you are renting because you have the keys, but some leases begin charging the next day. A move-out date may count if you keep the space until you hand back the keys. The option under More options lets you match your agreement. When the date is the last day of the month for a move-in, or the first for a move-out with no charge for that day, no days are charged and the result is $0.00.
What a proration does not cover
Proration splits one month of rent. It does not include a security deposit, utilities, application fees, pet fees or any change in rent mid-month. If the first month includes other charges, add them separately. To see the whole cost of getting settled, use the moving cost calculator, and to count days between two dates for a lease term, use the days between dates calculator.
Assumptions and limits
- The rent is one monthly amount and the move date falls within a single month.
- The actual-days method uses the real length of the month, including February in leap years. The 30-day method uses 30 for every month and treats day 31 as day 30.
- By default the move-in or move-out day itself is charged. You can change that under More options.
- Rounding is half up to the cent, using exact whole-cent math rather than binary decimals.
- Deposits, fees, utilities, mid-month rent changes and local proration rules are not modeled. Your lease and local law control. This is not legal advice.
Frequently asked questions
How do I calculate prorated rent?
Divide the monthly rent by the number of days in the month to get a daily rate, then multiply by the days you will occupy the unit. This tool does that and rounds to the nearest cent.
Should I prorate with 30 days or the real number of days?
Use whatever your lease states. If it is silent, the actual number of days in the month is the more common approach. The comparison table shows how much the choice changes the amount.
Is the day I move in included in the rent?
Often it is, because you can use the unit that day, but leases vary. A checkbox under More options lets you turn the charge for that day on or off so the result matches your agreement.
How is a move-out prorated?
Rent is charged from the first of the month through the move-out date, so moving out on the 15th costs 15 days of that month if the last day is counted. The tool shows both methods for the same date.
Why does the 31st behave differently in the 30-day method?
A 30-day month has no 31st, so the tool treats it as the 30th. A move-in on the 31st therefore charges one day, and a move-out on the 31st charges the full month.